In order to improve the performance of a golf club, club designers are constantly struggling to achieve a golf club with higher performance. One of the recent trends in improving golf club performance has been focused on improving the striking face of a metalwood golf club head.
The striking face of a metalwood golf club head is one of the most important component of a golf club head, as it is the only part that comes in contact with the golf ball. In order to maximize the performance of a golf club head, golf club designers have experimented with variables such as improving the coefficient of restitution (COR) as well as increasing the size of the “sweet zone”. The “sweet zone”, as generally known in the golf industry, relates to the zone of substantially uniform high initial velocity or a high COR. These concepts of “sweet zone” and COR have already been discussed by U.S. Pat. No. 6,605,007 to Bissonnette et al., and the disclosure of which is hereby incorporated by reference in its entirety.
One of the ways to create a larger “sweet zone” is illustrated in U.S. Pat. No. 8,318,300 to Schmitt et al., wherein a frontal wall of the striking face has a variable thickness. More specifically, U.S. Pat. No. 8,318,300 discussed how a golf club having a variable thickness will resist cracking bucking, and to efficiently transmit impact forces to the head top wall.
U.S. Pat. No. 7,682,262 to Soracco et al. expands upon the above basic concept of a variable face thickness by going on to establish the concept of “flexural stiffness”, wherein different flexural stiffness in the striking face can be achieved by different materials, different thicknesses, or a combination of both different material and different thicknesses.
Despite all of the advances in attempting to improve the performance of the striking face of the golf club head, none of the references are capable of adjusting the performance of the striking face without varying the material or thickness, both of which have some minor drawbacks. Varying the material of the striking face would require a bonding process to occur at the striking face portion, which could potentially crack when subjected to the high impact forced with a golf ball. Varying the thickness of the striking face, although eliminates the problem with cracking, would require additional mass at the striking face portion by thickening up certain parts of the striking face.
More importantly, none of the prior art recognize the ability to alter the Young's modulus of the same material used for the striking face portion to improve upon the performance of the golf club head.
Hence, based on the above it can be seen, there exists a need for an ability to alter the performance of a striking face of a golf club head that takes advantage of the inherent material property of the material by altering its Young's modulus. More specifically, there is a need in the field for a striking face of a golf club head wherein the Young's modulus of the striking face could be changed independent or in combination with the adjustment in altering the thickness.